Carbon nanotubes are expected to be used as the next-generation wiring material which replace Cu mainly used as a wiring material in semiconductor devices since they have excellent characteristics of electrical conductivity (low electrical resistance), thermal conductivity (high heat radiation), and current density resistance (high electromigration tolerance). In particular, since the aforementioned characteristics become apparent when the carbon nanotubes are made to have a high density, arranging the carbon nanotubes at a high density has been strongly demanded.
An arc discharge method, a laser ablation method, a liquid phase method, and a chemical vapor deposition method (hereinafter, referred to as “CVD method”) are known as a method for growing carbon nanotubes. The CVD method is preferably used in view of productivity, controllability, and semiconductor process consistency. A catalytic CVD method in which catalytic metal fine particles such as Fe, Co, Ni or the like are formed on a substrate and carbon nanotubes are grown using the catalytic metal fine particles as nuclei is generally used as the CVD method.
In the catalytic CVD method, a method of directly depositing fine particles onto a substrate, such as a sputtering method and an arc plasma gun, or a method of obtaining catalytic metal fine particles by performing plasma processing on a catalytic metal layer is used in order to obtain the catalytic metal fine particles (see, e.g., Patent Document 1).